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研究热噪声复合载荷作用下结构的动力学响应对高超声速飞行器结构的设计具有重要的指导意义,实验室多采用高温行波管进行热噪声复合试验研究,本文针对行波管中高温平板结构动力学响应预示方法进行研究。选取四边固支C/Si C材料平板为研究对象,首先研究热效应对平板结构固有模态特性的影响,然后在平板表面施加一维行波声载荷模拟行波管中声场,利用解析方法求解结构在热噪声复合载荷下的动力学响应。结果表明,在加热过程中平板固有频率先减小至极小值,而后逐渐回升。在固有频率下降阶段,材料弹性模量减小和热应力对于结构刚度的软化效应强于热变形的硬化效应;在固有频率回升阶段,热变形的硬化效用起决定性作用。线性响应范围内,平板在热噪声复合载荷下的加速度响应特性取决于其热模态。
The study of the dynamic response of the structure under thermal noise composite load has important guiding significance for the design of the hypersonic vehicle structure. The laboratory uses the high temperature traveling wave tube to do the thermal noise composite test. In this paper, Study prediction response method. Firstly, the effect of thermal effect on the inherent modal properties of flat plate structure is studied. Then one-dimensional traveling wave acoustic load is applied to the plate surface to simulate the acoustic field in traveling wave tube, and the analytical solution is used to solve the structure Dynamic Response Under Thermal Noise Combined Load. The results show that during the heating process, the natural frequency of the plate first decreases to the minimum and then gradually rises. The softening effect of the decrease of material elastic modulus and thermal stress on the structural stiffness is stronger than that of thermal deformation during the natural frequency descending phase. The hardening effect of thermal deformation plays a decisive role in the natural frequency recovery stage. Within the linear response range, the plate’s acceleration response under thermal noise composite loading depends on its thermal mode.